The present invention relates to polymers and more particularly to a copolyadipamide having hexamethyleneadipamide units and a minor portion of trimethylhexamethyleneadipamide units, and products prepared therefrom.
Polyadipamide polymers, e.g., polyhexamethyleneadipamide (nylon 66), have a number of positive characteristics, but are quite thermally unstable at their normal processing temperatures. When kept in the molten state at processing temperature for a long time, polyadipamides form branched/crosslinked, insoluble, nonfusible gel. The formation of gel in the polymer product and on the walls of processing equipment results in deficient product with poor processibility, particularly when fiber spinning is involved. The fiber spinning breaks which may occur are troublesome and make the winding of large yarn packages impractical.
Certain remedies to gel-formation have been reported such as in U.S. Pat. No. 3,872,055. U.S. Pat. No. 3,872,055 discloses a polyamide composition which has a decreased gel-forming property, specifically a copolyamide of the diamine-dicarboxylic acid type containing a phosphinic or phosphonous acid compound together with an alkali metal compound.